In 1775, a group of farmers from the areas of Lexington and Concord, Massachusetts, armed themselves with their own firearms and faced a well-equipped and well-trained professional army of redcoats.
These farmers wanted three things. Two were immediate and practical. Governor/General Thomas Gage had deployed the redcoats with two objectives: arrest John Hancock and Samuel Adams (both "Sons of Liberty" who, in today's language, would be called either "terrorists" or "insurgents;" and to seize the local militia's arsenal in Concord, which would render that region's colonists unable to resist the continued revokation of their rights.
The third reason was more idealistic. However, contrary to popular "textbook" opinion, it was not revolutionary. Englishmen had valued the concept of limited government and a social contract for over 500 years, going back all the way to Magna Carta (1215 AD).
The Proclamation of 1763 deprived colonists of their liberty and property rights (in the Ohio Valley, for which they fought the French and Indian War). To enforce the proclamation line, thousands of redcoats were garrisoned in forts scattered along the Appalachian frontier. This standing army during a time of peace was meant only to intimidate colonists--and government should fear the citizens, not the other way around. On top of this tyranny, taxes were necessary to fund these very same soldiers' quarters.
A year later, Parliament passed the Stamp Act. A basically direct tax with no purpose other than to raise revenues for the British government. The problem with this was that it taxed Englishmen (colonists) who had no representation in parliament. Magna Carta prohibits this, as did hundreds of years of English/British tradition. Colonists resisted this tyranny via organized protests/petitions (e.g. the Stamp Act Congress), boycotts on British goods, and "extra-legal" forms of Civil Disobedience, including the physical destruction of stamps as well as the tarring and feathering of royal officials.
Parliament repealed the Stamp Act in 1765, but replaced it with the Declaratory Act, which served as an effective "Blank Check" for Parliament. According to this act, they could tax and govern colonists regardless of representation in Parliament.
The Declaratory Act was followed by the Townshend Acts, a series of tariffs that would probably have been accepted by Americans as necessary to regulate trade. However, in the wake of the Stamp Act et al, Colonists were quite angry with the Townshend Acts. That the Townshend Acts allowed for writs of assistence--basically these were search warrants which required no probable cause and virtually no limits--only hastened the conflict. These were enacted in order for royal officials to better police colonial commerce--to catch and punish smugglers. While this seems perfectly correct in terms of government's power to maintain "law and order," colonists saw it as a tyrannical jab at their property rights. Remember, these taxes should never have been put in place to begin with. Boycotts and protests led to the repeal of most of the Townshend Acts, except for the one on tea.
The British East India Company enjoyed a state-established monopoly on the colonial tea industry. However, like all government subsidized industries, it ran its finances inefficiently and was in trouble. The tax on tea was meant to support The BEIC, and even though the tea was to be sold at bargain prices, agitators in Boston knew the real deal. Thus the Boston Tea Party was born. While many saw the attack against private property as a crime that was actually detrimental to the principles by which colonists were resisting British policy (I'm sorry for the complicated verbage), most colonists saw it for what it was. A bold act of civil disobedience. It's not like the BEIC was acting alone. It was acting as an arm of the British government, a tryannical body that no longer respected colonists' rights.
The Boston Tea Party was followed by the Coercive Acts, a series of punitive measures laid mostly against Boston (e.g. The Port Act closed the Port of Boston until the Tea from the Tea Party was paid for). It also called for further quartering of soldiers in colonists' (mostly Bostonians' homes), and a Quebec Act, which threatened to rob New England's local communities of their relative autonomy by placing them under the French laws of now British Quebec.
As things got worse in Boston, this led to the hunt for Hancock and Adams and the militia's arsenal (what I mentioned in the beginning).
A month before the battles of Lexington and Concord, Patrick Henry asked the House of Burgesses in Virginia what the British Ministry had done in the past ten years that had not been tyrannical and aimed at depriving colonists of their rights. He also called for war. He wasn't a prophet. He was a student of history.
Oh for the times when men stood up for their rights and did not content themselves to essentially meaningless rants....